What happened
On 1s February 2001, at approximately 08:10, a De Havilland DHC-6 Twin Otter, registration 8Q-TMA, was maneuvering on the water in the lagoon near Sun Island Resort. After completing a landing, the aircraft was operating near a floating platform when it collided with another De Havilland DHC-6 Twin Otter, registration 8Q-TMH, which was parked against the platform.
There were no passengers on either aircraft at the time of the collision, and the crew members sustained no injuries. The impact caused significant damage to the nose, cockpit area, and windscreens of 8Q-TMA, while 8Q-TMH sustained substantial damage to its port wingtip and aileron.
The investigation
The investigation examined the mechanical actions of the PT6 engines and the pilot's maneuvers. Investigators analyzed the process of feathering and unfeathering propellers, specifically looking at how the aircraft responded to power lever inputs. The inquiry also reviewed the operator's Standard Operating Procedures (SOPs) regarding propeller feathering and aircraft parking positions at the floating platform.
Findings
- The accident was caused by a pilot error involving the premature application of reverse thrust while the propellers were still transitioning out of the feathered position.
- The pilot overestimated the influence of the light northerly wind on the aircraft while the propellers were feathered.
- When the pilot moved the power levers aft to initiate reverse thrust before the blades had fully unfeathered, the resulting surge of thrust propelled the aircraft into the parked plane.
- There was a lack of standardization in parking procedures; the parked aircraft was positioned across the short axis of the platform rather than along the longitudinal axis.
- The operator's practice of feathering propellers while waiting on the water was inconsistent among crew members.
Safety action
Following the incident, the operator banned the practice of feathering propellers while waiting on the water and addressed inconsistencies in parking maneuvers. It was recommended that the company review and update its SOPs for water operations.